In vivo dosimetry device

Abstract

A device for in vivo dosimetry, the device comprising: a miniature probe ( 1 ) comprising at least: a radioluminescent material ( 3 ) that emits a radioluminescence signal of intensity that is a function of the high-energy radiation irradiating said material; and an optical fiber ( 4, 16 ) receiving the luminescence signal and conveying it to a luminescence detector system ( 14 ); and a luminescence detector system ( 14 ); the device being characterized in that the radioluminescent material ( 3 ) is gallium nitride (GaN) that emits a luminescence signal at least in a narrow band BE, and in that the luminescence detector system ( 14 ) includes an optical device ( 18 ) enabling the narrow emission band of gallium nitride to be selected.

1 . A device for in vivo dosimetry, the device comprising:
 a miniature probe ( 1 ) comprising at least:
 a radioluminescent material ( 3 ) that emits a radioluminescence signal of intensity that is a function of the high-energy radiation irradiating said material; and 
 an optical fiber ( 4 ,  16 ) receiving the luminescence signal and conveying it to a luminescence detector system ( 14 ); and 
   a luminescence detector system ( 14 );   the device being characterized in that the radioluminescent material ( 3 ) is gallium nitride (GaN) that emits a luminescence signal at least in a narrow band (BE), and in that the luminescence detector system ( 14 ) includes an optical device ( 18 ) enabling the narrow emission band BE of gallium nitride to be selected.   
   
   
       2 . A device according to  claim 1 , characterized in that the GaN radioluminescent material is doped specifically so that it emits essentially in the narrow emission band (BE). 
   
   
       3 . A device according to  claim 1 , characterized in that the GaN radioluminescent material is placed in a detection cavity ( 6 ) mounted on the end of an optical fiber or made at one of the ends of an optical fiber in order to form an invasive probe. 
   
   
       4 . A device according to  claim 3 , characterized in that the optical fiber ( 4 ) includes a tubular covering ( 7 ) for protecting optical cladding ( 8 ) that contains the core ( 9 ) of the optical fiber, the core ( 9 ) of the fiber and optionally the cladding ( 8 ) being removed over an end portion of the optical fiber in order to constitute the cavity ( 6 ) for receiving the radioluminescent material ( 3 ), this cavity being closed by a protective material ( 10 ). 
   
   
       5 . A device according to  claim 1 , characterized in that the probe ( 1 ) includes a reference optical fiber ( 41 ) identical to the fiber ( 4 ) connected to the luminescent material ( 3 ), but not connected to any radioluminescent material, the optical fiber ( 4 ) and the reference optical fiber ( 41 ) being connected via the optical selector device ( 18 ) to two identical photomultiplier tubes ( 17 ,  171 ) to enable differential measurements to be performed. 
   
   
       6 . A device according to  claim 1 , characterized in that each optical fiber ( 4 ,  41 ) is connected to a connector ( 15 ) that is connected via one or more link optical fibers ( 16 ,  161 ) to the luminescence detector system ( 14 ). 
   
   
       7 . A device according to  claim 1 , characterized in that the luminescence detector system ( 14 ) includes at least two detection channels on two different spectrum bands, one of which is the narrow band (BE) of GaN material. 
   
   
       8 . A device according to  claim 1 , characterized in that the luminescence detector system ( 14 ) includes, downstream from the optical selector device ( 18 ), a photodetector unit ( 17 ) comprising one or more photomultiplier tubes. 
   
   
       9 . A device according to  claim 1 , characterized in that the optical selector device ( 18 ) comprises a bandpass optical filter centered on the emission peak in the narrow band (BE) of GaN material ( 3 ). 
   
   
       10 . A device according to  claim 1 , characterized in that the optical selector device ( 18 ) comprises a dispersive or diffractive optical system ( 22 ) enabling the spectral components of the signal to be separated prior to being detected on two distinct spectrum channels using at least two photomultiplier tubes ( 17 ), one of which serves to detect the narrow band (BE) and is preferably provided with a narrow slit ( 24 ). 
   
   
       11 . A device according to  claim 1 , characterized in that the optical selector device ( 18 ) is preferably constituted by a collimator lens ( 25 ) and by a dispersive or diffractive optical system ( 22 ) that delivers the signal to the photoelectrical converter unit ( 17 ) made with the help of multichannel photomultiplier tubes. 
   
   
       12 . A device according to  claim 1 , characterized in that the luminescence detector system ( 14 ) includes means for synchronizing the time window (F) on the high-energy pulse shots (t) relating to radio therapy treatment.